Study of Pt-free anode catalysts for anion exchange membrane fuel cells

Unsupported transition-metal nanoparticles such as Ni, Co, and Ni(x)Co(y) (Ni(0.75)Co(0.25), Ni(0.50)Co(0.50), Ni(0.25)Co(0.75)) were synthesized by the liquid reduction process for application to the anode catalyst of Precious Metal-free Liquid feed Fuel Cells (PM-fLFCs) using hydrazine hydrate (N(2)H(4)center dot H(2)O) for a fuel. Their electrocatalytic activities were evaluated by rotating disk electrode (RDE), and the mass activity of Ni(0.50)Co(0.50) exhibited higher activity than other catalysts for the anodic oxidation of hydrazine in alkaline solution. The morphology and structure of these catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoemission spectroscopy (XPS). It has been indicated that Ni(0.50)Co(0.50) has a coexistence effect by inhabitation of Co oxidation and significantly improve the electrooxidation of hydrazine. The excellent fuel cell performance, 0.891V of open circuit voltage and 432mW/cm(2) of high maximum power, was exhibited using Ni(0.50)Co(0.50) catalysts. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.